Tests for Nasopharyngeal Cancer

Nasopharyngeal cancer (NPC) is most often diagnosed when a person goes to a doctor because of symptoms such as a lump in the neck or stuffy nose, but no signs of a cold. The doctor will take a history and do an exam. The patient may then be sent to see an ear, nose and throat (ENT) specialist. The nasopharynx is hard to examine. Most other kinds of doctors do not have the specialized training or equipment to do a thorough exam of this part of the body.

Medical history and physical exam

If you have signs or symptoms that suggest you might have NPC, the doctor will want to get your complete medical history. You will be asked about the changes you've noticed, possible risk factors, and your family history.

A physical exam will be done to look for signs of NPC or other health problems. A more thorough exam of your nasopharynx will be done. During the exam, the doctor will pay special attention to your head and neck, including your nose, mouth, and throat; your facial muscles; and the lymph nodes in your neck. A hearing test may also be done.

Exams of the nasopharynx

The nasopharynx is deep inside the head and isn't easily seen, so special techniques are needed to examine this area. There are 2 main types of exams used to look inside the nasopharynx for abnormal growths, bleeding, or other signs of disease. Both types are usually done in the doctor's office.

For indirect nasopharyngoscopy, the doctor uses special small mirrors and bright lights to look at the nasopharynx and nearby areas.

For direct nasopharyngoscopy, a fiber-optic scope known as a nasopharyngoscope to look directly at the lining of the nasopharynx. The scope is a thin, flexible, lighted tube that's put in through your nose. Numbing medicine is sprayed into your nose before the exam to make it easier. This is the method most often used to carefully examine the nasopharynx.

If a tumor starts under the lining of the nasopharynx (in the tissue called the submucosa), the doctor may not be able to see it. Because of this, imaging tests, like CT or MRI scans (see below), may be needed.

Biopsy

Symptoms and the results of exams can suggest that a person might have NPC, but the only way to be sure is by taking out cells from the abnormal area and looking at them under a microscope. This is called a biopsy. Different kinds of biopsies may be done, depending on where the abnormal area is.

Endoscopic biopsy

If a suspicious growth is seen in the nasopharynx, the doctor may take out a tiny piece of it with small instruments and the aid of a fiber-optic scope. Often, biopsies of the nasopharynx are done in the operating room as an outpatient procedure. The tissue sample is then sent to a lab, where a pathologist (a doctor who specializes in diagnosing and classifying diseases in the lab) looks at it under a microscope. If the biopsy sample contains cancer cells, the pathologist sends back a report describing the type of the cancer.

NPC cannot always be seen during an exam. If a person has symptoms suggesting NPC but nothing looks abnormal on exam, the doctor may biopsy normal-looking tissue, which may be found to contain cancer cells when looked at under the microscope.

Fine needle aspiration (FNA) biopsy

An FNA biopsy may be used if you have a suspicious lump in or near your neck. To do this, the doctor puts a thin, hollow needle into the lump. The needle is attached to a syringe which is used to aspirate (withdraw) a few drops of fluid containing cells and tiny bits of tissue. The skin where the needle will be inserted might be numbed with a local anesthetic, but sometimes this isn't needed.

The cells are then looked at under a microscope to see if they're cancer cells.

An FNA biopsy can show if an enlarged lymph node in the neck is caused by a response to an infection, the spread of cancer from somewhere else (such as the nasopharynx), or a cancer that starts in lymph nodes – which is called a lymphoma. If the cancer started somewhere else, the FNA biopsy alone might not be able to tell where it started. But if a patient already known to have NPC has enlarged neck lymph nodes, FNA can help find out if the spread of NPC caused the swelling.

Imaging tests

Imaging tests use x-rays, magnetic fields, sound waves, or radioactive particles to make pictures of the inside of your body. Imaging tests may be done for a number of reasons, including to help find a suspicious area that might be cancer, to learn how far cancer may have spread, and to help see if treatment is working.

Chest x-ray

If you've been diagnosed with NPC, a plain x-ray of your chest may be done to see if the cancer has spread to your lungs. This is very unlikely unless your cancer is far advanced. If the results are normal, you probably don’t have cancer in your lungs.

Computed tomography (CT) scan

The CT scan is an x-ray test that produces detailed cross-sectional images of your body.

A CT scan of the head and neck can provide information about the size, shape, and position of a tumor and can help find enlarged lymph nodes that might contain cancer. CT scans or MRIs are important in looking for cancer that may have grown into the bones at the base of the skull. This is a common place for nasopharyngeal cancer to grow. CT scans can also be used to look for tumors in other parts of the body.

Magnetic resonance imaging (MRI) scan

Like CT scans, MRI scans make detailed images of soft tissues inside the body. But MRI scans use radio waves and strong magnets instead of x-rays. A contrast material called gadolinium is often injected into a vein before the scan to better see details.

MRIs can be used to try to find out if the cancer has grown into structures near the nasopharynx. MRIs are a little better than CT scans at showing the soft tissues in the nose and throat, but they’re not quite as good for looking at the bones at the base of the skull, a common place for NPC to grow.

Positron emission tomography (PET) scan

PET scans use a form of radioactive sugar that's put into the blood. Because cancer cells in the body are growing rapidly, they absorb large amounts of the sugar. After about an hour, you lie on the table for about 30 minutes while a special camera creates a picture of areas of radioactivity in the body. The picture is not finely detailed like a CT or MRI scan, but it provides helpful information about your whole body. Some machines are able to do both a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET with the more detailed appearance of that area on the CT.

Your doctor may use this test to see if the cancer has spread to your lymph nodes. It can also help give the doctor a better idea of whether an abnormal area on a chest x-ray may be cancer. A PET scan can also be useful if your doctor thinks the cancer may have spread but doesn’t know where.

Blood tests

Blood tests are not used to diagnose NPC, but they may be done for other reasons, such as to help find out if the cancer has spread to other parts of the body.

Routine blood counts and blood chemistry tests

Routine blood tests can help determine a patient’s overall health. These tests can help diagnose nutrition problems, anemia (low red blood counts), liver disease, and kidney disease. And they may suggest the possibility of spread of the cancer to the liver or bone, which may lead to more testing.

Epstein-Barr virus (EBV) DNA levels

Tests to measure the blood level of EBV DNA may be done before and after treatment to help show how well treatment is working.

National Comprehensive Cancer Network, Clinical Practice Guidelines in Oncology (NCCN Guidelines®), Head and Neck Cancers, Version I.2018 -- February 15, 2018. Accessed at www.nccn.org/professionals/physician_gls/pdf/head-and-neck.pdf on April 23, 2018.